Exposing apparatus for photographic contact printing



1952 1.. P. F. VAN DER GRINTEN 2,585,519

EXPOSING APPARKTUS FOR PHOTOGRAPHIC CONTACT PRINTING Filed July 16, 1947INVENTOR LODEWIdK PIETER FRANS VAN DER GRINTEN Y W QM V ATTORNEYSPatented Feb. 12, 1952 UNITED STATES OFFICE EXPOSING' APPARATUSFOR.PHOTOv GRAPHIC GONTA'CTIPRINTING Application July16, 1947, Serial No.761,314

In the Netherlands July 17, 1946 2 Claims.

This invention relates to an exposing apparatus for photographiccontact-printing wherein flexible sheet materials such as an originaland a light-sensitive film or paper are exposedtolight inclose contactwith each other. The apparatus involved is of the type equipped withahollow cylinder of light-pervious material which .511!- rounds a lightsource,.and with a flexible applying sheet for applying and holding thesheet materials to be exposed against the surface of the cylinder.

In exposing apparatus of this type the cylinder generally consists ofglass and the applyingsheet is made of cloth or the like. The materialtobe exposed is usually rotated with the cylinder or pushed over itssurface in the course of exposure, so that exposure talresrplace whilethe material is moving. In some cases it is desirable to expose thematerial while it is stationary; for example, when the originals to be.copied varyin t";

transparency or translucency and require difierent periods of exposurefor proper treatment. vIn such cases an apparatus adapted for stationaryexposure is the simplest to use. In. apparatus of that type the size ofthe material that can be exposed is limited according to the diameter ofthe cylinder, and this is important. because the diameter of thecylinder is subject topractical limitations. It is easier to obtain aflawless glass cylinder with a small diameter, and the cylinder must beflawless in the case of stationary exposure. Secondly, a cylinder ofsmall diameter makes it possible to use a lamp of lower power, also oneof smaller length, in, the case of tubular lamps, and this presentsadvantages with respect both to the cost of electric current and to thecooling of the lamp.

Inorder to have the size of the sheetmaterlal that can be exposed aslargeasfeasible'itimust be'possible to use the largest feasiblepart. ofthe circumference of the cylinder for exposure. This becomes-possible ifthe flexible applying sheet is made movable onto and from the cylinderas the cylinder is rotated back and forth for the introduction and theremoval, respectively, of the material to be exposed. To accomplishthis, however, the applying sheet normally must be fastenedto thecylinder alonga generating line. of its surface, and that involves otherdifliculties. In such event a relative adjustment of the applying sheetand the cylinder-,e. g., in order to remove glass'flaws' from the fieldof exposure or to correct any slanting tendency of the applying sheet,is not possible. Also, the replacement of a glass cylinder broken orcracked during operation is a complicated matter.

According to the present invention, these dimculties-may be overcome byproviding the applying sheet with a lengthening extension in theform'of'two drawing members located oneither side of the sheet beyondits breadth, such as spaced parallel cords, wires, tapes, belts,ribbons, ropes,- etc., and passing the interconnected applying sheet andextension about the cylinder in the form of a loop so that portions ofthe same cross each other and extend away from the cylinder in oppositedirections with the applying sheet passingbetween the .two drawingmembers where they'cross.

This and other features of the present inven- 1 tion will be apparentfrom the followingdetailed description of an illustrative embodimentthereof and from the accompanying illustrative drawing which forms apart hereof, and in which:

Fig. 1 is a vertical-cross section of anexposing apparatus embodying theinvention;

Fig. 2 is a diagrammatic representation of the manner of'arranging theapplying sheet and its drawing members about the cylinder; and

Fig. 3 is a fragmentary plan view showing details. of one manner ofconnecting the applying sheetwith the drawing members.

As seen in Figs. 1 and 2, a glass cylinder I that is to be used forexposure is arranged horizontallyso as to be'rotatable about its axis.The cylinder'is ,made rotatable by having its surface rest on upperportions of horizontally spaced series of rotary discs 3 and 4 and whichare carried on spaced horizontal shafts or rods 3a and 411,respectively. These shafts or rods are mounted in the frame 20. Locatedinside and on the axis of cylinder! is a tubular lamp 2, which isslightly longer than the cylinder. A flexible applying cloth isdesignated 5 and possesses a length at least rsufiicient to encircle thecylinder l. ends of this cloth are provided with transverse rods. '6 and1 (Fig. 1), which. extend through terminal hems 5a and 512,respectively, of the cloth so thatthe ends of the rods project beyondthe .breadthofthe' cloth on either side thereof as seen,..for example.at Baand 6b in Fig. 3.

The projecting ends of the rods 6 and l are interconnected by spaced,parallel flexible drawing members a and 9, which may be ribbons. cords,or'the like as mentioned above. Thus the applying sheet 5 and thedrawing members 8 and 9 together .form an-endless belt member. As may beseen particularly from Fig. 2, this endless belt member is passed orwrapped about the glass cylinder in the form of a loop thereon, andwhere the belt portions extending from the loop across each other toleave the cylinder, 1. e., where The with its surface.

the sheet 5 itself moves to and from the surface of the cylinder, thebody of the sheet 5 lies and may pass freely in the space between thetwo drawing members 8 and 9. Thus the applying sheet 5 is renderedcapable of being passed or wound onto the cylinder I so far that it willcover the full 360 of the surface of the cylinder; which is to say thatthe glass cylinder can now perform one complete revolution and canaccommodate sheet material to be exposed, between itself and the sheet5, over the full sweep of its circumference. A complete utilization ofthe surface of the glass cylinder is therefore made possible.

As shown in Fig. 1, the portions of the applying sheet 5 and the drawingmembers 3 and 9 that extend oppositely away from the cylinder I leadfrom it over spaced horizontal pulleys or rollers i0 and ll below thecylinder, and thence together again beneath these rollers in endlessbelt arrangement. One of the rollers, as at H2, i held in the frame 28below and toward the back of cylinder I, while the other roller H whichreceives the sheet 5 is held between forward extensions 20a of the frameat the front of the apparatus. The length of the endless belt member andthe forward spacing of the front roller II are such that the portion ofsheet 5 extending between cylinder I and roller ll constitutes a tablesurface at l2 ahead of the cylinder. A fixed guiding plate l3 presents aflat surface just below the applying sheet at l2, to support theapplying sheet there so that an original and a light-sensitive sheet tobe exposed may be easily placed on it for movement by it into contactwith the exposing cylinder.

In order to keep the requisite tension in the endless belt member, thedrawing members 8 and 9 may each be made with an elastic portion such asa tension spring [4. The frame 20 is provided with a covering hood 2!for complete enclosure of the exposing cylinder. Hood H is hinged to theframe at 22 and has a handle 23 to facilitate opening the hood.

When a photo copy is to be made, the original to be copied is placed onthe surface of the applying sheet 5 at l2, together with thelightsensitive sheet material to be exposed. Then the applying sheet ispushed into the apparatus in the direction of arrow l5, the glasscylinder 5 thus being rotated until the materials have been moved orwound completely thereupon in contact These materials may possess anywidth accommodated by the axial length of the cylinder and any length upto a maximum equalling the outside circumference of the cylinder. Thematerials thus applied to the surface of the cylinder are held there bythe applying sheet and exposed to the light transmitted through theglass cylinder from the tubular lamp. After due exposure the applyingsheet 5 is moved back in the direction of arrow [6, the glass cylinderthus also being turned back so that the sheet materials arrive again atthe table location [2 where they may be removed for replacement byanother set of materials to be exposed.

A stripper I has an edge held next to the surface of the cylinder labove plate [3, in position to strip on any material that may tend tostick to the cylinder as it is turned back for the removal of materialsafter an exposure. The

stripper I1 is made impervious to the light from lamp 2, and it is sodisposed between the lamp and the table surface at I2 that it acts notonly as a stripper but also as a light screen to keep the effectivelight from falling on sensitive material at I2.

I claim:

1. An apparatus for exposing flexible sheet materials in photographiccontact printing, comprising a hollow rotatable cylinder oflightpervious material, a light source within the cylinder and aflexible sheet for applying said sheet materials to the surface of thecylinder for exposure, said flexible applying sheet being of a lengthsuflicient to substantially encircle the cylinder and having connectedwith at least one of its ends a lengthening extension in the form ofspaced flexible drawin members located on either side of the body of thesheet, the interconnected sheet and extension passing about the cylinderas a loop thereon from which portions of said sheet and extension,respectively, extend in opposite directions so that they cross eachother adjacent the cylinder with the sheet passing between the spaceddrawing member, said drawing members being connected with both ends ofsaid sheet so that the sheet and the drawing members together constitutean endless belt.

2. An apparatus for exposing flexible sheet materials in photographiccontact printing, comprising a light-pervious cylinder rotatable about ahorizontal axis, a light source within the cylinder on its axis, spacedhorizontal rollers below and parallel to the axis of the cylinder, oneroller back of the cylinder and another spaced in front thereof, aflexible applying sheet of a length sufficient to substantially encirclethe cylinder and having a lengthening extension connected with the endsof the sheet to form therewith an endless belt member, said extensioncomprising spaced flexible drawing members located on either side of thebody of the sheet, said belt member passing about the cylinder as a loopthereon from which portions of the sheet and the drawing members,respectively, extended in opposite directions in crossed relationship atthe lower side of the cylinder with the sheet passing forward throughspace between the drawing members, the extending portions of said sheetand said drawing members leading to and over said front and said backrollers, respectively, and then together beneath said rollers, the sheetportion extending between the cylinder and said front rollerconstituting a table surface for receiving sheet materials to be appliedto and exposed on the cylinder, said drawing members comprising elasticportions holding the belt member on the cylinder and the rollers undertension.

LODEWIJK PIETER FRANS VAN DER GRINTEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 704,232 Bell July 8, 1902 789,773Wagenhorst May 16, 1905

